Freezers will often produce frost due to air moisture condensing and then freezing on the cooling coils in the course of normal operation. The frost reduces the efficiency of the freezer. Conventional methods of removing the frost from the cooling coils include the methods and apparatus disclosed in U.S. Pat. No. 4,570,447. The '477 patent discloses removing the frost by directing a current of compressed air over the cooling coil batteries. Referring to FIG. 1, which is a FIGURE of the '447 patent, a typical freezer is shown having a plurality of cooling coils 38 (refrigeration coils). A tank 30 is mounted on a wheeled carriage 34, which in turn is supported on tracks 36. The tank 30 is supplied by the air inlet hose 32 and includes a plurality of nozzles. Some of the nozzles are oriented in one direction and some of the nozzles are oriented in an opposite direction. In this way, the tank 30 can move back and forth by opening the valves to the nozzles pointed in one direction and then opening the valves to the nozzles pointed in the other direction.
FIG. 2, also from the '447 patent, shows another typical apparatus for removing frost from cooling coil batteries. The air nozzle apparatus includes two pipes 3 and 4 directed toward the cooling coil battery 1. The pipes are supplied with compressed air through a hose 19. The pipes are connected to a chain sprocket wheel 15, which in turn is intermeshed with an endless loop chain 10 looped around wheels 11 and 12. The sprocket 15 is further attached to a support post 7 which is guided along the rail 8. Further, a driving unit, such as a motor, can be linked to turn any one of the sprocket wheels 11, 12, or 15. Therefore, the chain can be driven to one side or the other thereby causing the pipes to rotate at the same time the assembly is moved back and forth, thereby removing the frost from the cooling coil batteries.